Parts washers including solvent recirculating and cleaning systems are well known and widely accepted in industries ranging from typewriter repair to aircraft maintenance shops for cleaning and decontaminating dirty, greasy parts and tools. Such washers are rapidly replacing the inconvenient and unsafe gasoline filled bucket as a way of cleaning dirty parts and tools.
The patented art is replete with examples of parts washers. Most include a sink for washing the parts including a solvent supplying hose which is directed over the parts by the operator, a tank containing a solvent supply, a pump for recirculating solvent through the sink and some sort of filtration system for removing contaminants from the solvent before it is reused. To date, such filtration systems are deficient to a greater or lesser degree in that either the solvent must be replaced after being recirculated only a few times, thus resulting in unnecessary inconvenience and expense, or the filtration system, if efficient, is complex and is soon clogged with contaminants whereby the washer must be disassembled for cleaning the filters and then reassembled for use. Obviously, this time consuming procedure is equally unsatisfactory.
Eary examples of parts washers are evidenced in U.S. Pat. Nos. 2,653,617, 2,677,381; and 2,746,647. Some are expressly designed for service station use and thus include a compressed air connection for circulating the solvent or cleaning fluid, as disclosed in U.S. Pat. Nos. 2,897,830 and 3,352,310. In U.S. Pat. No. 3,020,918, liquid is circulated to agitate the parts as they are washed. The filtration problem has led to some exotic proposed solutions, such as a series of stacked sediment receiving and holding trays as in U.S. Pat. No. 2,675,012 and a divided tank arrangement with a primary sludge or sediment trap as disclosed in U.S. Pat. No. 3,343,555.
Other patents disclosing parts washers include U.S. Pat. Nos. 3,016,841; 3,378,019 and 3,416,544. This listing is by no means exhaustive of the patented art but merely exemplary.
Parts washers which have enjoyed commercial success include a parts washer manufactured by the Safety-Kleen Corporation of Elgin, Illinois which is disclosed in U.S. Pat. No. 3,522,814. A removable plastic liner or bag is provided for easily discarding accumulated contaminants and dirty solvent and the sink cover has a fusible link which melts in the case of fire to reduce the danger of further fire or an explosion by closing the cover. Another parts washer is manufactured by Solv-X, Inc. of Ontario, Canada. This device also has a removable plastic bag; a water layer at the bottom of the tank collects heavier debris while denser oils and greases collect at the top of the water layer beneath the solvent. A conical filter is arranged over a recirculating pump beneath the sink drain, in the tank. Aesthetics has a role in parts washers; Solv-X, Inc. is the assignee of U.S. Pat. No. D232,322.
Remote environment filter assemblies having spaced, concentric layers are disclosed in prior U.S. Pat. Nos. 410,767; 2,314,048; and 3,349,919.
The instant invention overcomes the disadvantages of prior art parts washers such as discussed above by providing a tank arrangement and filter assembly allowing for prolonged recirculation of solvent without need of frequently changing the solvent together with an efficient but simplified filtration system wherein components are easily and efficiently cleaned.